Global target analysis of picosecond chlorophyll fluorescence kinetics from pea chloroplasts : A new approach to the characterization of the primary processes in phostosystem Ⅱ α-and β-units

Roelofs, Theo A.,Lee, Choon-Hwan,Holzwarth, Alfred R. 부산대학교 유전공학연구소 1992 분자생물학 연구보 Vol.8 No.-

In this study, we have used the method of target analysis to analyze the ps fluorescence kinetics of pea chloroplasts with open (F_0) and closed (F_max) photosystem Ⅱ (PS Ⅱ) centers Extending the exciton/radical pair equilibrium model (Schatz G H H Brock, and A R Holzwarth 1988 Biophys J 54 397-405) to allow for PS Ⅱ heterogeneity, we show that two types of PS Ⅱ (labeled α and β) must be accounted for each pool being characterized by its own-set of molecular rate constants within the model. Simultaneous global target analysis of the data at F_0 and F_max results in a detailed description of the molecular kinetics and energetics of the primary processes in both types of PS Ⅱ units This characterization revealed 'that the PS Ⅱα pool accounts for twice as many Chl molecules as PS Ⅱβ, which suggests a PSⅡα/PSⅡβ reaction center stoichiometry of close to unity. By extrapolation it is shown that the primary charge separation in hypothetical "isolated β reaction centers is slower than in isolated α reaction centers in open centers bv a factor of 4 (1/k^int_1 = 11 vs 29 ps), in closed centers by a factor of 2 (1/k^int_1 = 34 vs 19 ps). Despite this slower charge separation process in PS Ⅱβ the quantum efficiency of the charge separation process is hardly affected a charge stabilization yield at F_1 (i e , P^+ IQ_A^-) of 86% (as compared to 90% in PS Ⅱα). Reduction of Q_A (closing PS Ⅱ) has distinctly different effects on the primary kinetics of PS Ⅱβ, as compared to PS Ⅱα. In PS Ⅱα the charge separation rate drops by a factor of 6, whereas the charge recombination process is hardly affected In PS Ⅱβ the charge separation is slowed down by a factor of 3, whereas the charge recombination rate increases by a factor of 5 in terms of charges in standard free energy the reduction to Q_A - lifts the free energy of the radical pair P-I-relative to the excited state (Chl_n/P)^* by 47 meV in PS Ⅱα and by 67 meV in PS Ⅱβ The concomitant increase in fluorescence quantum yield is the same for both types of PS Ⅱ These results snow that PS Ⅱα and PS Ⅱβ exhibit a different molecular functioning with respect lo the primary processes which might have its origin in a different molecular structure of the reaction centers and/or a different local environment of these centers Location in different parts of the thylakoid membrane might be involved We also applied different error analysis procedures to determine the error ranges of the values found for the molecular rate constants. It is shown that the commonly used standard error has very little meaning as it assumes independence of the fit parameters Instead an exhaustive search procedure accounting for all possible correlations between the fit parameters gives a more realistic view on the accuracy of the fit parameters.

Modular cocycles and cup product

Bruggeman, Roelof,Choie, YoungJu Elsevier 2019 Advances in Mathematics Vol.351 No.-

<P><B>Abstract</B></P> <P>The Eichler-Shimura isomorphism relates holomorphic modular cusps forms of positive even integral weight to cohomology classes. The Haberland formula uses the cup product to give a cohomological formulation of the Petersson scalar product.</P> <P>In this paper we extend Haberland's formula to modular cusp forms of positive real weight. This relation is based on the cup product of an Eichler cocycle and a Knopp cocycle.</P> <P>We may also consider the cup product of two Eichler cocycles. In the classical situation this cup product is almost always zero. However we show evidence that for real weights this cup product may very well be non-trivial. We approach the question whether the cup product is a non-trivial coinvariant by duality with a space of entire modular forms. The cup product yields a bilinear map over C from pairs of holomorphic modular forms (not necessarily of the same weight, one of them may have large growth at the cusps) to coinvariants in infinite-dimensional modules. To investigate whether this bilinear map is non-trivial we test the result against entire modular forms of a suitable weight. Under some conditions on the weights, this leads to an explicit triple integral, which can be investigated numerically, thus providing evidence that the cup product is non-trivial at least in some situations.</P>

Vision-based Autonomous Disinfection of High-touch Surfaces in Indoor Environments

Sean Roelofs,Benoit Landry,Myra Kurosu Jalil,Adrian Martin,Saisneha Koppaka,Sindy K.Y. Tang,Marco Pavone 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

Autonomous systems have played an important role in response to the Covid-19 pandemic. Notably, there have been multiple attempts to leverage Unmanned Aerial Vehicles (UAVs) to disinfect surfaces. Although recent research suggests that surface transmission is less significant than airborne transmission in the spread of Covid-19, surfaces and fomites can play, and have played, critical roles in the transmission of Covid-19 and many other viruses, especially in settings such as child daycares, schools, offices, and hospitals. Employing UAVs for mass spray disinfection offers several potential advantages, including high-throughput application of disinfectant, large scale deployment, and the minimization of health risks to sanitation workers. Despite these potential benefits and preliminary usage of UAVs for disinfection, there has been little research into their design and effectiveness. In this work, we present an autonomous UAV capable of effectively disinfecting indoor surfaces. We identify relevant parameters such as disinfectant type and concentration, and application time and distance required of the UAV to disinfect high-touch surfaces such as door handles. Finally, we develop a robotic system that enables the fully autonomous disinfection of door handles in an unstructured and previously unknown environment. To our knowledge, this is the smallest untethered UAV ever built with both full autonomy and spraying capabilities, allowing it to operate in confined indoor settings, and the first autonomous UAV to specifically target high-touch surfaces on an individual basis with spray disinfectant, resulting in more efficient use of disinfectant.

Chemical Ecology: Decoding the Signals of Insects

wendell L. Roelofs 한국응용곤충학회 2005 한국응용곤충학회 학술대회논문집 Vol.2005 No.05

Clark-Hall 모델을 이용한 한반도 상의 강수사례에 대한 수치모의 실험

김영준,서광수,정관영,엄원근,이동규,Janice Coen,Roelof T. Bruintjes,Terry L. Clark 한국기상학회 1997 한국기상학회 학술대회 논문집 Vol.1997 No.-

Isolation and Identification of Blattellaquinone, the Female Volatile Sex Pheromone of the German Cockroach

S. Nojima,C. Schal,F. Webster,W. Roelofs 한국응용곤충학회 2005 한국응용곤충학회 학술대회논문집 Vol.2005 No.05

Energetic, ∼5-90 keV neutral atom imaging of a weak substorm with STEREO/STE : STEREO/STE ENA IMAGING OF WEAK SUBSTORM

Wang, Linghua,Lin, R. P.,Parks, G. K.,Brandt, P. C.,Roelof, E. C.,Sample, J. G.,Eastwood, J. P.,Larson, D. E.,Curtis, D. W.,Luhmann, J. G. American Geophysical Union 2010 Geophysical research letters Vol.37 No.8

Reidentification of pheromone composition of Sparganothis sulfureana (Clemens) and evidence of geographic variation in male responses from two US states

Junwei Zhu,Kye-Chung Park,Carolyn Garvey,Daniel Mahr,Satoshi Nojima,Wendell Roelofs,Tom Baker,Sridhar Polavarapu 한국응용곤충학회 2009 Journal of Asia-Pacific Entomology Vol.12 No.4

GC-EAD analyses of pheromone gland extracts of calling female Sparganothis sulfureana revealed at least 6 compounds that consistently elicited antennal responses from male antennae. In addition to the major pheromone compound, (E)-11-tetradecenyl acetate (E11–14:OAc), which was previously reported, the other compounds were found to be (E)-9-dodecenyl acetate (E9–12:OAc), (Z)-9-dodecenyl acetate (Z9–12:OAc), (Z)-9-tetradecenyl acetate (Z9–14:OAc), (Z)-11-tetradecenyl acetate (Z11–14:OAc), and (E)-11-tetradecenol (E11–14:OH). Tetradecyl acetate, hexadecyl acetate and hexadecenyl acetates were also present in the extracts, but elicited no EAG response frommale antennae. Wind tunnel tests demonstrated that males from NewJersey responded equally well to a blend containing five pheromone components in relative to the pheromone glands of calling females. Different male-response profiles from field-trapping tests conducted in the states of Wisconsin and NewJersey were observed, respectively. Significantly higher numbers of male S. sulfureana were caught in New Jersey in traps baited with the binary blend of E11–14:OAc (30 μg) with 1% of Z11–14:OAc, but males from Wisconsin responded equally well to traps containing blends of E11–14:OAc with 0–10% of Z11–14: OAc. The addition of more than 10% of Z11–14:OAc to the primary pheromone compound reduced male captures significantly in both states. Male catches were doubled by adding E9–12:OAc and E11–14:OH to the most attractive binary blend in both states. The trapping test with caged live virgin female moths showed that males in Wisconsin preferred females from the local population than those from NewJersey. The differences in male responses observed may indicate the existence of pheromone polymorphism in this species. GC-EAD analyses of pheromone gland extracts of calling female Sparganothis sulfureana revealed at least 6 compounds that consistently elicited antennal responses from male antennae. In addition to the major pheromone compound, (E)-11-tetradecenyl acetate (E11–14:OAc), which was previously reported, the other compounds were found to be (E)-9-dodecenyl acetate (E9–12:OAc), (Z)-9-dodecenyl acetate (Z9–12:OAc), (Z)-9-tetradecenyl acetate (Z9–14:OAc), (Z)-11-tetradecenyl acetate (Z11–14:OAc), and (E)-11-tetradecenol (E11–14:OH). Tetradecyl acetate, hexadecyl acetate and hexadecenyl acetates were also present in the extracts, but elicited no EAG response frommale antennae. Wind tunnel tests demonstrated that males from NewJersey responded equally well to a blend containing five pheromone components in relative to the pheromone glands of calling females. Different male-response profiles from field-trapping tests conducted in the states of Wisconsin and NewJersey were observed, respectively. Significantly higher numbers of male S. sulfureana were caught in New Jersey in traps baited with the binary blend of E11–14:OAc (30 μg) with 1% of Z11–14:OAc, but males from Wisconsin responded equally well to traps containing blends of E11–14:OAc with 0–10% of Z11–14: OAc. The addition of more than 10% of Z11–14:OAc to the primary pheromone compound reduced male captures significantly in both states. Male catches were doubled by adding E9–12:OAc and E11–14:OH to the most attractive binary blend in both states. The trapping test with caged live virgin female moths showed that males in Wisconsin preferred females from the local population than those from NewJersey. The differences in male responses observed may indicate the existence of pheromone polymorphism in this species.

The Tissue Origin and Culture History of Mesenchymal Stem Cells Affect their Performance in Osteoblastic Differentiation

( Lieke C. J. Van Den Berk ),( Bas J. H. Jansen ),( Kim G. C. Siebers Vermeulen ),( Tonnie Huijs ),( Helene Roelofs ),( Gesine Kogler ),( Carl G. Figdor ),( Ruurd Torensma ) 한국조직공학·재생의학회 2011 조직공학과 재생의학 Vol.8 No.1

Mesenchymal Stem Cells (MSC) are quiescent and located in several vascular niches where they serve as a stem cell reservoir. When MSC are mobilized into peripheral tissues they are able to differentiate into various mesodermal cell lineages such as osteocytes, chondrocytes, and adipocytes, depending on the local micro-milieu. MSC can be tremendously expanded in vitro. This prompted us to compare the differentiation potential after short and long term expansion of two different MSC isolates, i.e. a cell type isolated from umbilical cord blood (UCB) and a cell type from bone marrow (BM). UCB-MSC maintain their proliferative properties for an extended period of time before they reach senescence. UCB-MSC and BM-MSC are both capable of differentiating towards the osteogenic lineage though expression of alkaline phosphatase (ALP) and matrix mineralization was much more pronounced in UCB-MSC. Regarding adipogenic differentiation, UCB-MSC were not able to form oil droplets upon differentiation while BM-MSC readily could. We furthermore show that long-term culture affects the differentiation potential of MSC lines from both origins. Interestingly, the ageing occurring due to long term culture does not alter the immunogenic properties of MSC.

Metagenomic analysis of bacterial community structure and diversity of lignocellulolytic bacteria in Vietnamese native goat rumen

Do, Thi Huyen,Dao, Trong Khoa,Nguyen, Khanh Hoang Viet,Le, Ngoc Giang,Nguyen, Thi Mai Phuong,Le, Tung Lam,Phung, Thu Nguyet,Straalen, Nico M. van,Roelofs, Dick,Truong, Nam Hai Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.5

Objective: In a previous study, analysis of Illumina sequenced metagenomic DNA data of bacteria in Vietnamese goats' rumen showed a high diversity of putative lignocellulolytic genes. In this study, taxonomy speculation of microbial community and lignocellulolytic bacteria population in the rumen was conducted to elucidate a role of bacterial structure for effective degradation of plant materials. Methods: The metagenomic data had been subjected into Basic Local Alignment Search Tool (BLASTX) algorithm and the National Center for Biotechnology Information non-redundant sequence database. Here the BLASTX hits were further processed by the Metagenome Analyzer program to statistically analyze the abundance of taxa. Results: Microbial community in the rumen is defined by dominance of Bacteroidetes compared to Firmicutes. The ratio of Firmicutes versus Bacteroidetes was 0.36:1. An abundance of Synergistetes was uniquely identified in the goat microbiome may be formed by host genotype. With regard to bacterial lignocellulose degraders, the ratio of lignocellulolytic genes affiliated with Firmicutes compared to the genes linked to Bacteroidetes was 0.11:1, in which the genes encoding putative hemicellulases, carbohydrate esterases, polysaccharide lyases originated from Bacteroidetes were 14 to 20 times higher than from Firmicutes. Firmicutes seem to possess more cellulose hydrolysis capacity showing a Firmicutes/Bacteroidetes ratio of 0.35:1. Analysis of lignocellulolytic potential degraders shows that four species belonged to Bacteroidetes phylum, while two species belonged to Firmicutes phylum harbouring at least 12 different catalytic domains for all lignocellulose pretreatment, cellulose, as well as hemicellulose saccharification. Conclusion: Based on these findings, we speculate that increasing the members of Bacteroidetes to keep a low ratio of Firmicutes versus Bacteroidetes in goat rumen has resulted most likely in an increased lignocellulose digestion.